1. Field of the Invention
The present invention is directed to an automobile manufacturing line, and in particular, to an automobile manufacturing line which is laid out in a generally spiral arrangement.
2. Description of the Prior Art
Prior art automobile manufacturing lines, such as disclosed in Japanese Laid-Open Publication No. 6-49255 are arranged with different manufacturing process lines being arranged parallel to one another with conveyor loops located at the ends of the parallel manufacturing lines, to carry a workpiece from one line to the next line. This prior art arrangement provides a zig-zag line layout.
The above-described prior art manufacturing line arrangement with a zig-zag layout, is an improvement over a straight line layout, in that it reduces the walking distance between manufacturing process lines and it also shortens the overall length of the automobile manufacturing line.
However, in the zig-zag layout of the automobile manufacturing line, in order to deliver parts to a manufacturing process line in the interior of the zig-zag, it is necessary to use an overhead conveyor in order to avoid parallel manufacturing lines located in front of the manufacturing line to which the part is being delivered. The use of the overhead conveyors decreases the efficiency and makes it more difficult to coordinate the delivery operation.